wrangled QWidgets to allow for resizable tracks with track headers

app/widget/timelinewidget/trackview/trackviewsplitter.cpp

@@ -0,0 +1,109 @@
+#include "trackviewsplitter.h"
+
+#include <QDebug>
+#include <QPainter>
+
+#include "trackviewitem.h"
+
+TrackViewSplitter::TrackViewSplitter(Qt::Alignment vertical_alignment, QWidget* parent) :
+  QSplitter(Qt::Vertical, parent),
+  alignment_(vertical_alignment)
+{
+  setHandleWidth(1);
+
+  int initial_height = 0;
+
+  if (alignment_ == Qt::AlignBottom) {
+    // Add empty spacer so we get a splitter handle after the last element
+    addWidget(new QWidget());
+  }
+
+  for (int i=0;i<3;i++) {
+    TrackViewItem* w = new TrackViewItem();
+    addWidget(w);
+
+    initial_height += w->sizeHint().height() + handleWidth();
+  }
+
+  if (alignment_ == Qt::AlignTop) {
+    // Add empty spacer so we get a splitter handle after the last element
+    addWidget(new QWidget());
+  }
+
+  setFixedHeight(initial_height);
+}
+
+void TrackViewSplitter::HandleReceiver(TrackViewSplitterHandle *h, int diff)
+{
+  int ele_id = -1;
+
+  for (int i=0;i<count();i++) {
+    if (handle(i) == h) {
+      ele_id = i;
+      break;
+    }
+  }
+
+  // The handle index is actually always one above the element index
+  if (alignment_ == Qt::AlignTop) {
+    ele_id--;
+  } else if (alignment_ == Qt::AlignBottom) {
+    diff = -diff;
+  }
+
+  QList<int> element_sizes = sizes();
+
+  int old_ele_sz = element_sizes.at(ele_id);
+
+  // Transform element size by diff
+  int new_ele_sz = old_ele_sz + diff;
+
+  // Validate it with the widget's minimum size
+  new_ele_sz = qMax(new_ele_sz, widget(ele_id)->minimumHeight());
+
+  // Correct diff
+  diff = new_ele_sz - old_ele_sz;
+
+  // Set new size on element
+  element_sizes.replace(ele_id, new_ele_sz);
+  setSizes(element_sizes);
+
+  // Increase height by the difference
+  setFixedHeight(height() + diff);
+}
+
+QSplitterHandle *TrackViewSplitter::createHandle()
+{
+  return new TrackViewSplitterHandle(orientation(), this);
+}
+
+TrackViewSplitterHandle::TrackViewSplitterHandle(Qt::Orientation orientation, QSplitter *parent) :
+  QSplitterHandle(orientation, parent),
+  dragging_(false)
+{
+}
+
+void TrackViewSplitterHandle::mousePressEvent(QMouseEvent *)
+{
+}
+
+void TrackViewSplitterHandle::mouseMoveEvent(QMouseEvent *)
+{
+  if (dragging_) {
+    static_cast<TrackViewSplitter*>(parent())->HandleReceiver(this, QCursor::pos().y() - drag_y_);
+  }
+
+  drag_y_ = QCursor::pos().y();
+  dragging_ = true;
+}
+
+void TrackViewSplitterHandle::mouseReleaseEvent(QMouseEvent *)
+{
+  dragging_ = false;
+}
+
+void TrackViewSplitterHandle::paintEvent(QPaintEvent *)
+{
+  QPainter p(this);
+  p.fillRect(rect(), palette().base());
+}